Spatial light modulator, holographic three-dimensional image display including the same, and method for modulating spatial light

A holographic image display comprising:

• a writing optical system comprising a first light source that radiates writing light;
• a reproduction optical system comprising a second light source that radiates reproduction light;
• and
• an image display unit disposed between the writing optical system and the reproduction optical system, wherein the image display unit comprises a spatial light modulator that comprises a plurality of pixels and a light addressing unit that addresses light from the writing optical system to each pixel of the optical light modulator, wherein the spatial light modulator comprises:
• a variable refractive index layer having a refractive index which is variable in each of the plurality of pixels based on one of an optical signal and an electrical signal,
• a metal layer that is disposed on an upper surface of the variable refractive index layer, wherein light incident on the metal layer causes the generation of a surface plasmon at an interface between the variable refractive index layer and the metal layer, and
• a high refractive index layer that is disposed on the metal layer, wherein a refractive index of the high refractive index layer is higher than a maximum refractive index of the variable refractive index layer,
• wherein the surface plasmon moves along the interface between the variable refractive index layer and the metal layer and is reflected from the variable refractive index layer to modulate a phase of light incident on the variable refractive index layer, and a moving distance of the surface plasmon, in a horizontal direction along the interface between the variable refractive index layer and the metal layer, is smaller than a pitch of two adjacent pixels, thereby increasing a spatial resolution of the spatial light modulator.

A method for modulating light, whereby a phase of light incident on a plurality of pixels of a spatial light modulator is modulated, the method comprising:

• changing a refractive index of a variable refractive index layer in each of the plurality of pixels based on one of an optical signal and an electrical signal;
• generating a surface plasmon by radiating reproduction light onto a metal layer disposed on the variable refractive index layer;
• and
• changing a phase of light reflected from the variable refractive index layer via the surface plasmon along an interface between the variable refractive index layer and the metal layer and is reflected from the variable refractive index layer, wherein a moving distance of the surface plasmon, in a horizontal direction along the interface between the variable refractive index layer and the metal layer, is smaller than a pitch of two adjacent pixels of the spatial light modulator, thereby increasing the spatial resolution of the spatial light modulator.